The present invention relates to connecting pieces for establishing a light propagating transition between two single mode optical waveguides having respectively different cross sections.
Arrangements for transmitting and processing signals by means of optical waves normally operate best when single mode waveguides are used in the components themselves and as connectors therefor. However, occasionally, or even frequently, this requires the connection of waveguides having respectively different cross-sectional configurations. The fundamental mode, which is the only mode conducted by single mode waveguides, loses power in these transitions due to radiation and the radiated power may interfere if it is collected at another part of the arrangement where it can give rise to crosstalk or other interference phenomena. Both effects--radiation losses and interference radiation--must normally be suppressed as well as possible.